Hypodermic syringe



Jan. 27, l1953 J. c. NADEAU HYPODERMIC SYRINGE Filed Marh 19, 1951 Fig.

./ o/m G. Nadeau IN V EN TOR.

BY @Mm Attorneys Patented Jan. 27, 1953 UNITED STATES PATENT OFFICE 2,626,664 HYPDERMIC 4'sYRlNomr John fdnaaeau, Detroit, Mieli. Application March 19, 1951, "Serial No. 216,389

This invention relates` to syringes, and more particularly to hypodermic syringes of improved construction and operation.

It is'known that the pain accompanying the insertion of a hypodermic is felt asI the needle is being forced into the flesh. Substantially no `pain is felt while the needle is in the flesh or when `it is' withdrawn therefrom. Furthermore, when the needle is inserted fast enough there is practically no painat all, because the nerve system does'not have suicient time to carry the sensation to the brain before the insertion is accomplished.

It is a principal object ofthe present invention, accordingly, to provide a hypodermic syringe which operates lautomatically and so' speedily with respect to insertion of theneedle tha-tno pain or substantially no irritating sensation is felt during use of the syringe.

A further object of 'the inventionis to provide an improved hypodermic syringe wherein v-acuum means is utilized in conjunction with the atmospheric pressure for supplying power'to drive the needle during insertion `of the same into the iiesh.

AnotherV object vis to provide animproved' hypodermic syringe having a trigger-operated hypodermic needle, and wherein the fs'ame may be automatically and instantaneously 'forced into the iiesh upon'release of the trigger mechanism.

The invention'consists in certain otherifeatures of construction and in the combination andarrangement of the parts as hereinafterV described and illustrated inthe accompanying drawings.

In the drawings:

Figure l is an elevational view of a hypodermic ,syringe embodying the features of this invention;

Figure 2"is a vertical Vsectional view taken. on theline 2-2 of Figure .1 and looking inthe direction of the arrows;

Figure '3 is a plan view ofthe syringe shown* in Figure 1 and taken from the top thereof;

Figure 4 is `a cross-sectional view taken substantially Onthe lineV 4-4 and looking'inthe direction of the arrows;

Figurey 5 is'a tfragmentary detail View of the upper body portion of the syringe and illustrating 'the groove structure for controlling the'air admis- Sion tothe vacuum chamber;

'Figure 6 is a similar view as Figure 5 and illustrating the relative position of the grooves lduring the power operating stroke of .the syringe;

.Figure 7 is fa cross-sectional view taken substantially on the line 1 1 of Fig. 5 and looking in the direction of the :arrows yand taken onFig- .ure 5; and

7 Claims. (Cl. 128K-2118) Figure 8 is a similar cross-sectional view taken on the line 8--8 of Figure 6 and looking in the direction ofthe arrows.

Referring to the drawings in more detail, the syringe shown in Figures l and 2 vcomprises a tubular body I0 which is preferably formed of heat Vresistant glass, and having a cylindrical chamber I2 in which is slip-fitted a hollow glass piston I4. This piston consists of an elongated neck I6 of reduced diameter which is slidably mounted in the reduced bore I8 of the tubular body I0, as best shown in Figure 2.

A- central'passage 20 is provided in the neck I6 which communicates with the medicament chamber 2I of the hollow piston I4. The outer end portion of the neck I6 consists of a reduced extension 22 `having a portion 23 which is adapted to receive the complementaryshank or cup 24 of a hollow hypodermic needle 26.

In the syringe structure illustrated, a guard member or capv 28 of suitable -shape is'adapted to be tted on the end of the reduced diameter head 36 of the tubular body I0. A collar 32 on the upper end of the guard 28 isk provided with bayonet slots 34 for lockingly receiving detents or keeper pins 36 on the head portion 36.

A plunger 40, which is preferably formed of heat-resistant glass, similarly as the piston I4, is slip-fitted in'the'cylindrical chamber 2I and is arranged vto be reciprocated therein, as by grasping'the head portion 44. The upper end of the hollow piston I4 is provided with a flanged head portion 46 and a depending lug 48, the latter being a trip or trigger and adapted to engage the top of the tubular body I0, as at 50. The head portion of the tubular body I0 is biiurcated, as at 52 `and. 54, being provided withv diametrically disposed, longitudinal slots or notches 56 and 58. The slot 56 is of narrow Width so as to substantially t the lug 46, whereas the slot 58 is wider than the slot 56 so as to permit some freedom of movement of the piston I4, for reasons further described.

Due to the close fitting of the parts I0 and I2, it will be observed that by partial withdrawal of the piston I4 a vacuum will be created in the space 60 existing between the parts in the lower part of the tubular chamber I2. Further, in order to relieve this vacuum as desired when the hypodermic needle 26 is to be withdrawn, the inner wall of the tubular body I0 is provided with a longitudinally extending air groove 64. A similar air groove 66 is formed on the outer wall of the slidably engaging piston I4. Thus, when the lug 48 is in the elongated .cut-away slot 58, the parts may be relatively rotated and adjusted so that the air grooves 64 and 66 coincide or overlap, as indicated at 'I0 in Figures 5 and 7, so that air is admitted to the chamber 60, releasing the vacuum. In order to provide a, shock absorber for movement of the piston I4 against the lower end of the chamber 60, a rubber or similar plastic gasket 'I2 is provided in the lower part of the chamber, as shown in Figure 2.

In operation of the hypodermic syringe, the plunger 4E] is removed and the drug to be used is introduced into the chamber 2| (Fig. 2). Thereafter the plunger is replaced and the hollow piston I4 is grasped and withdrawn upwardly so as to position the lug 48 over the top of one of the edge flanges 52 or 54 so as to hold the lpiston withdrawn and thus creating a vacuum in the chamber 60. During this withdrawal of the hollow cylinder-piston I4, the air grooves B6 and 64 will, of course, be out of registration. When it is desired to insert the hypodermic needle 26 into the flesh, the lower end of the guard 28, as at B, is placed on the skin where the desired insertion is to be made, and the head portion 45 turned relative to the bodyy I0 so that the lug 43 will engage in the narrow groove or notch 56. In this position, the force of the trapped air or vacuum will act and the plunger will be driven rapidly forwardly so as to automatically and forcibly drive the hypodermic needle 26 into the patients flesh.

It will be seen from the foregoing that the body I acts as an outside cylinder and that the extended head portion 3E provides a Satisfactory guide for the needle-carrying neck I 6 on the inside cylinder I4. The cylinder I4 is also in the nature of a piston in that it reciprocates in snug tting telesccping relation in the chamber I2 as is obvious. This tight t between the cylinder I0 and the piston I4 provides the aforementioned suction or vacuum space 60 which constitutes the ways and means to provide the necessary force for driving the hypodermic needle into the flesh of the patient in an obvious manner. The lug 43 is a trip and just as soon as it is rotated from the position shown in dotted lines in Figure 3 to the full-line position shown in Figure 4, the snap action of the piston I4, acting under the influence of the vacuum in the chamber B and the atmospheric pressure, eX- erted on the exposed surfaces of the barrel, becomes effective, produces an expelling force and drives the hypodermic needle into the flesh. This is one phase of the operation.

The other phase of the operation isY for permitting dismantling or separation of the parts for cleansing. In this connection, it may be stated that the detachable cap 28 can be used at the time of driving the needle into the skin, or it may be used merely as a protecting cap when the over-all construction is not in use. Insofar as grooves 64 and 66 are concerned, it is necessary, of course, to employ these merely for purposes of enabling the user to bodily withdraw the piston I from the chamber I2. Since the wide notch 58 is diametrically opposite to the narrower notch 56, it is necessary to hold the outer cylinder IB in one hand and to turn the complete hypodermic needle assembly around so that the lug or trip 48 now registers with the wider notch 58 as shown in Figures 5 and 6. By moving the lug 43 from the position in Figure 6 to that shown in Figure 5, the two grooves 66 and 54 are communicatively lined up and when in this position they serve to form a vent. The vent obviously relieves Vthe suction pull in the space 60 and allows the cylinder I4 and plunger 40, as a complete unit, to be Withdrawn from the outer cylinder I0. Otherwise, because of the snug t between the piston I4 and the outer cylinder ID, it would not be possible to separate these parts for cleansing.

In view of the foregoing description taken in conjunction with the accompanying drawings, it is believed that a clear understanding of the device Will be quite apparent to Athose skilled in this art. A more detailed description is accordingly deemed unnecessary.

Minor changes in shape, size, materials and arrangement of parts may be resorted to in actual practice without departing from the spirit and scope of the invention as claimed.

Having described the invention, claimed as new is 1. An automatically injected hypodermic syringe assembly of the class described comprising a tubular body deiining an` outer cylinder, said cylinder being open at opposite ends, the outer end thereof being reduced and constituting a guide, a cylindrical barrel, said barrel being tted for reciprocation in said outer cylinder and constituting a piston, said barrel being provided with a reduced extension operable through said guide and provided with a hollow hypodermic needle, the inner end of said piston being provided with rlnger gripping means and a retaining trip the latter being releasably engageable with the coacting end of said outer cylinder, corresponding ends of said outer cylinder and piston when relatively adjusted by withdrawing the piston partially from said cylinder being adapted to provide a vacuum creating space.

2. The str-ucture specified in claim l .together with a readily attachable and detachable protector cap carried by the outer end of said outer cylinder and enclosing said needle.

3. A hypodermic syringe and means for forciblyinjecting the needle thereof into the patients esh comprising, in combination, an elongated tubular body definingl an outer cylinder, said body being provided at one end with a guide and being provided at its opposite end with diametrically opposite notches and radially outstanding flanges constituting ledge members, a barrel constituting a hollow piston and being mounted for reciprocation in the bore of said outer cylinder, the outer endof said barrel being provided with a hypodermic needle slidably mounted in said guide, the outer ends of said outer cylinder and barrel being adapted to be spaced apart to provide a vacuum creating chamber, and a plunger slidably and removably mounted in said barrel.

LA hypodermic syringe and means for forcibly injecting the needle thereof into the patients what is viiesh comprising, in combination, an elongated tubular body defining an outer cylinder, said body being provided at one end with a guide and being provided at its opposite end with diametrically opposite notches andV radially outstanding flanges constituting ledge members, a barrel, said barrel constituting a hollow piston and being mounted for reciprocation in the bore of said outer cylinder, the outer end of said barrel being provided with a hypodermic needle slidably mounted in said guide, the outer ends of said outer cylinder and barrel when spaced apart being adapted to thus provide a temporary vacuum creating chamber, a plunger mounted in said barrel, said barrel being provided at one end with head means having an outstanding lug, said lug being releasably and rotatably engageable with said flanges and being adapted to be selectively registered with said notches.

5. In a structure of the class described, in combination, a tubular body defining an outer cylinder provided at its outer end with guide means, a hypodermic needle embodying a barrel, sald barrel constituting a piston and being mounted for reciprocation in the bore of said outer cylinder, the interior surface of said outer cylinder having an air venting groove, the exterior surface of said barrel having an air venting groove and said grooves being adapted to be selectively aligned and disaligned according to the discretion of the user, and a plunger slidably mounted in said barrel.

6. The structure specified in claim wherein said outer cylinder is provided at one end with at least one trip action notch, the corresponding end of said barrel being provided with a lug and said lug constituting a trip and said trip being adapted to be engaged with one end of said outer cylinder when the piston is withdrawn for purposes of momentarily creating a vacuum between the piston and outer cylinder and said trip being adapted to be lined up with said notch and allowed to recede into said notch to permit the atmospheric pressure, exerted on the exposed surfaces of said barrel, to become effective and to thereby produce an expelling force which actuates the barrel and needle relative to said outer cylinder.

7. A hypodermic syringe comprising, in com- 6 bination, an outer cylinder provided at one end with trip retaining and releasing means, a projectible and retractible piston mounted for reciprocation in said cylinder and having one end projectible forcibly through and beyond the other end of said cylinder, a hypodermic needle carried by said one end of said piston, cooperating portions of said cylinder and piston, inwardly of said needle, having coacting spaced surfaces providing a vacuum chamber, the other end of said piston having a manually regulable trip which is optionally engageable with said trip retaining and releasing means, said piston being hollow and providing an inner medicament containing cylinder, the latter in medicament delivering communication with said needle, and a medicament expelling plunger reciprocable in said inner cylinder.

JOHN C. NADEAU.

REFERENCES' CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 938,597 Lombardo Nov. 2, 1909 1,234,582 Trueblood July 24, 1917 1,279,069 Yoshida Sept. 17, 191B 1,845,036 Busher Feb. 16, 1932 2,472,116 Maynes June 7, 1949 

